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Nutritional Deficiencies (Malnutrition)

What are nutritional deficiencies?

The body requires many different vitamins and minerals that are crucial for both body development and preventing disease. These vitamins and minerals are often referred to as micronutrients. They aren’t produced naturally in the body, so you have to get them from your diet.

A nutritional deficiency occurs when the body doesn’t absorb or get from food the necessary amount of a nutrient. Deficiencies can lead to a variety of health problems. These can include digestion problems, skin disorders, stunted or defective bone growth, and even dementia.

The amount of each nutrient you should consume depends on your age. In the United States, many foods that you buy in the grocery store (such as cereals, bread, and milk) are fortified with nutrients that are necessary to prevent nutritional deficiency. But sometimes your body is unable to absorb certain nutrients even if you’re consuming them.

Keep reading to learn about some common nutritional deficiencies and how to avoid them.

Types of nutritional deficiency

It’s possible to be deficient in any of the nutrients your body needs. Some common types of nutritional deficiencies include:

Iron deficiency

The most widespread nutritional deficiency worldwide is iron deficiency. Iron deficiency can lead to anemia, a blood disorder that causes fatigue, weakness, and a variety of other symptoms.

Iron is found in foods such as dark leafy greens, red meat, and egg yolks. It helps your body make red blood cells. When you’re iron-deficient, your body produces fewer red blood cells. The red blood cells it produces are smaller and paler than healthy blood cells. They’re also less efficient at delivering oxygen to your tissues and organs.

According to the World Health Organization (WHO), over 30 percent of the world’s population has this condition. In fact, it’s the only nutritional deficiency that’s prevalent in both developing and industrialized countries. Iron-deficiency anemia affects so many people that it’s now widely recognized as a public health epidemic.

Vitamin A deficiency

Vitamin A is a group of nutrients crucial for eye health and functioning and reproductive health in men and women. It also plays a part in strengthening the immune system against infections.

According to WHO, a lack of vitamin A is the leading cause of preventable blindness in children. Pregnant women deficient in vitamin A have higher maternal mortality rates as well. Beta-carotene is a nutrient that functions as an antioxidant and is found in red, orange, yellow, and dark green pigmented produce. Beta-carotene can be converted to vitamin A in the body when needed.

For newborn babies, the best source of vitamin A is breast milk. For everyone else, it’s important to eat plenty of foods high in vitamin A. These include:

Thiamine (vitamin B-1) deficiency

Another common nutritional deficiency occurs with thiamine, also known as vitamin B-1. Thiamine is an important part of your nervous system. It also helps your body turn carbohydrates into energy as part of your metabolism.

A lack of thiamine can result in weight loss and fatigue as well as some cognitive symptoms such as confusion and short-term memory loss. Thiamine deficiency can also lead to nerve and muscle damage and can affect the heart.

In the United States, thiamine deficiency is most often seen in people who chronically abuse alcohol. Alcohol reduces the body’s ability to absorb thiamine, store thiamine in the liver, and convert thiamine to a usable form. Thiamine deficiency is a common cause of Wernicke-Korsakoff syndrome, a form of dementia.

Many breakfast cereals and grain products in the United States are fortified with thiamine. Eggs, legumes, nuts, seeds, wheat germ, and pork are also good sources of the vitamin.

Niacin (vitamin B-3) deficiency

Niacin (vitamin B-3) is another mineral that helps the body convert food into energy. A severe deficiency of niacin is often referred to as pellagra. Niacin is found in most animal proteins, but also in peanuts. As a result, this condition is rare in developed countries or in meat-eating communities.

Symptoms of pellagra include diarrhea, dementia, and skin disorders. You can usually treat it with a balanced diet and vitamin B-3 supplements.

Folate (vitamin B-9) deficiency

Vitamin B-9, often referred to as folate, helps the body create red blood cells and produce DNA. It also helps brain development and nervous system functioning. Folic acid is the synthetic form found in supplements or fortified foods.

Folate is especially important for fetal development. It plays a crucial role in the formation of a developing child’s brain and spinal cord. Folate deficiency can lead to severe birth defects, growth problems, or anemia.

You can find folate in foods, including:

  • beans and lentils
  • citrus fruits
  • leafy green vegetables
  • asparagus
  • meats such as poultry and pork
  • shellfish
  • fortified grain products
  • whole grains

While beans can provide great folate, the folate content in canned beans is about half of what cooked dried beans offer.

Most people in the United States get enough folate. But pregnant women and women of childbearing age sometimes don’t consume enough folate for a healthy pregnancy. The National Institutes of Health (NIH) recommends that women who are pregnant or who may become pregnant consume up to 400 milligrams of folate or folic acid each day to help prevent birth defects.

There’s also research showing that some people have genetic mutations that prevent their body from methylating folate, or converting it a form the body can use. In these cases, while folate intake might be adequate, a supplement of methylated folate may be necessary to prevent deficiency.

Vitamin D deficiency

According to Harvard’s School of Public Health, about 1 billion people worldwide are affected by vitamin D deficiency. People with darkly pigmented skin are at a higher risk of vitamin D deficiency.

Vitamin D is essential for healthy bones. It helps the body maintain the right levels of calcium in order to regulate the development of teeth and bones. A lack of this nutrient can lead to stunted or poor bone growth. Osteoporosis, caused by a lack of calcium and vitamin D, can lead to porous and fragile bones that break very easily.

The best source of vitamin D is sunlight. Vitamin D is only found naturally in a few foods. Foods with vitamin D include:

Many dairy products and plant milks in the United States are fortified with vitamin D.

Ultraviolet light from the sun is also a source of vitamin D. According to the NIH, research suggests that 5 to 30 minutes of sun exposure twice a week on the face, arms, neck, or back can provide you with enough vitamin D.

Although recommended for UV protection, sunscreen does hinder vitamin D absorption from sunlight through the skin. Spend a few minutes in the sun prior to sunscreen for optimal vitamin D absorption.

Calcium deficiency

Calcium helps your body develop strong bones and teeth. It also helps your heart, nerves, and muscles work the way they should. A calcium deficiency often doesn’t show symptoms right away, but it can lead to serious health problems over time. If you aren’t consuming enough calcium, your body may use the calcium from your bones instead, leading to bone loss.

While some experts believe that calcium deficiencies may be related to low bone mass and weakening of bones due to osteoporosis, it’s a topic of much debate. According to the World Health Organization (WHO), evidence does support the importance of calcium with vitamin D in older populations for bone health, but evidence is weaker for younger populations.

Population study research by WHO also reveals that countries with lower calcium intake don’t have high rates of bone diseases. But countries with higher calcium intake have higher rates of hip fractures. In these countries, like the United States, high protein intake and lack of exercise can contribute to poor calcium status and bone health.

Calcium deficiency can lead to convulsions and abnormal heart rhythms. They can even be life-threatening. Postmenopausal women experience greater bone loss due to changing hormones and have more trouble absorbing calcium.

The best sources of calcium are dairy products such as milk, yogurt, cheese, calcium-set tofu, and small fish with bones. Vegetables such as kale and broccoli also have calcium, and many cereals and grains are calcium-fortified.

What causes nutritional deficiencies?

The usual cause of nutritional deficiencies is a poor diet that lacks essential nutrients. The body is able to store some nutrients, so a deficiency may not be caught until it’s been without the nutrient for some time.

A number of diseases and conditions — including colon cancer, imbalanced gut flora, and gastrointestinal conditions like Crohn’s and celiac disease — can lead to an iron deficiency. Pregnancy can also cause a deficiency if the body diverts iron to the fetus.

Researchers have found associations between bariatric surgery, which reduces the size of the stomach to achieve weight loss, and nutritional deficiency. People who are candidates for bariatric surgery may already be nutrient-deficient due to poor diet. Before and after the surgery, you should talk to your doctor and dietitian to set up a thorough nutrition plan.

What are the symptoms of nutritional deficiencies?

The symptoms of a nutritional deficiency depend on which nutrient the body lacks. However, there are some general symptoms you might experience, including:

You may display all of these symptoms or only groups of them. Over time, most people adapt to the symptoms. This can cause the condition to go undiagnosed. Schedule a checkup with your doctor if you experience prolonged periods of fatigue, weakness, or poor concentration. These symptoms could be a sign of the beginning of a serious deficiency.

How are nutritional deficiencies diagnosed?

Your doctor will discuss your diet and eating habits with you if they suspect you have a nutritional deficiency. They’ll ask what symptoms you’re experiencing. Make sure to mention if you’ve experienced any periods of constipation or diarrhea, or if blood has been present in your stool.

Your nutritional deficiency may also be diagnosed during routine blood tests, including a complete blood count (CBC). This is often how doctors identify anemia.

How are nutritional deficiencies treated?

The treatment for a nutritional deficiency depends on the type and severity of the deficiency. Your doctor will find out how severe the deficiency is, as well as the likelihood of long-term problems caused by the lack of nutrients.

They may order further testing to see if there’s any other damage before deciding on a treatment plan. Symptoms usually fade when the correct diet is followed or nutrient is supplemented.

Dietary changes

A doctor may advise you on how to change your eating habits in the case of a minor deficiency. For example, people with anemia should include more meat, eggs, poultry, vegetables, and iron-rich grains in their diet.

Your doctor may refer you to a dietitian if your deficiency is more severe. They may recommend keeping a food diary for a few weeks. When you meet with the dietitian, you’ll go over the diary and identify any changes you should make.

Typically, you’ll meet with your dietitian regularly. Eventually, you may have a blood test to confirm that you’re no longer deficient.


The United States’ official dietary guidelines recommends that you get most of your nutrients from food. In some cases, you may need to take supplements or a multivitamin. It may also be necessary to take an additional supplement to help your body absorb the supplements, such as taking calcium and vitamin D together.

The frequency and dosage of a supplement will depend on how severe the deficiency is. This will be decided by your doctor or a dietitian.

You should talk to your doctor before taking any nutritional supplements.

Parenteral administration

In very severe cases — such as when a nutritional deficiency doesn’t respond to oral medications or vitamins — it may be necessary for the nutrient to be given parenterally, or through the veins or muscles.

This can carry the risk of additional side effects. It’s usually done in a hospital.

Parenteral iron, for example, can cause side effects that include:

In rare cases, it can even cause a severe allergic reaction. Once you’ve been given the treatment, your doctor will have you do a repeat blood test to confirm that it was successful. You may need to attend the hospital for repeat appointments until you’re no longer deficient.

Will a nutritional deficiency cause long-term problems?

Most problems caused by nutritional deficiencies will stop once you’re no longer deficient. But in some cases, there may be lasting damage. This usually only occurs when the deficiency has been severe and has lasted a long time.

For example, a prolonged thiamine deficiency can be associated with stunted growth or depression. Nutritional deficiencies in children can be serious and lead to lasting negative health outcomes.

If you’re experiencing symptoms and are concerned that you’re not obtaining enough of a certain nutrient, talk to your doctor. They can discuss your diet with you and help figure out whether you should make some dietary changes or start taking supplements.

Content licensed from:

Written by: The Healthline Editorial Teamon: Jul 25, 2017

This feature is for informational purposes only and should not be used to replace the care and information received from your health care provider. Please consult a health care professional with any health concerns you may have.
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